Honda 2005 VTX1800C Owner's Manual page 112

Oil Recommendation
API
classification
viscosity
(weight)
JASO T 903
standard
SG or higher
except oils
labeled as energy
conserving on the
circular API
service label
SAE 10W-40
MA
Engine Oil & Filter
suggested oil
Pro Honda GN4 or HP4 (without
molybdenum additives) 4-stroke
oil (USA & Canada), or Honda
4-stroke oil (Canada only), or an
equivalent motorcycle oil.
Suggested oils are equal in
performance to SJ oils that are not
labeled as energy conserving on the
circular API service label.
Servicing Your Honda
103